Department of Psychology, University of Georgia.
Peter Boris Centre for Addiction Research, St. Joseph's Healthcare Hamilton, McMaster University.
Psychol Bull. 2019 Feb;145(2):141-164. doi: 10.1037/bul0000181.
Given the robust behavioral association between delayed reward discounting (DRD) and addictive behavior, there is an expanding literature investigating the neural correlates of this relationship. The objective of this systematic review was to characterize and critically appraise the existing literature examining the neural correlates of DRD in individuals exhibiting addictive behavior using functional and structural MRI (fMRI/MRI) and to do so through the lens of the neural networks implicated in addiction. Using a systematic search strategy, 20 studies were identified, with 12 focusing on task fMRI, 4 focusing on functional connectivity fMRI, and 4 focusing on structural MRI. Behaviorally, significantly steeper DRD was present in individuals with addictive disorders across studies, reproducing earlier findings. Among individuals with addictive disorders, there was substantial evidence of greater neural activity in the executive control network during choices for larger-delayed rewards (delayed gratification) relative to choices for smaller-immediate rewards (immediate gratification), particularly in dorsolateral prefrontal cortex, as well as moderate evidence of greater recruitment of the default mode, salience, and reward valuation networks during larger-delayed choices. In functional connectivity fMRI studies, there was moderate evidence for greater connectivity between the executive control, salience, and default mode networks in individuals exhibiting addictive behavior. Structural MRI studies reported highly heterogeneous findings and no consistent conclusions could be drawn. As a whole, this review suggests consistent differences in neural activation and connectivity relating to DRD in individuals with addictive disorders. It also reveals heterogeneity of methods and findings in this line of inquiry. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
鉴于延迟奖励折扣（DRD）与成瘾行为之间存在强大的行为关联，因此有越来越多的文献研究了这种关系的神经相关性。本系统综述的目的是描述和批判性地评价使用功能和结构磁共振成像（fMRI/MRI）检查表现出成瘾行为的个体中 DRD 的神经相关性的现有文献，并通过涉及成瘾的神经网络来进行研究。使用系统搜索策略，确定了 20 项研究，其中 12 项侧重于任务 fMRI，4 项侧重于功能连接 fMRI，4 项侧重于结构 MRI。在行为上，在具有成瘾障碍的个体中，DRD 明显更陡峭，再现了早期发现。在具有成瘾障碍的个体中，有大量证据表明，与选择较小即时奖励（即时满足）相比，在选择较大延迟奖励（延迟满足）时，执行控制网络中的神经活动更大，尤其是在背外侧前额叶皮层，以及在较大延迟选择中默认模式、突显和奖励估值网络的中度证据更大的招募。在功能连接 fMRI 研究中，在表现出成瘾行为的个体中，执行控制、突显和默认模式网络之间的连通性有中度证据。结构 MRI 研究报告了高度异质的发现，无法得出一致的结论。总的来说，本综述表明，具有成瘾障碍的个体的 DRD 与神经激活和连接存在一致差异。它还揭示了该研究领域方法和发现的异质性。
